Electric switch.



H. G, THOMPSON.

ELECTRIG SWITCH.

APPLICATION FILED NOV. 12. 1909.

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ELECTRIC SWITCH.

APPLICATION FILED NOV. 12, 1909.

Patented Feb.13,1917.

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UNITED STATES PATENT OFFICE.

HARRISON G. THOMPSON, OF GLEN RIDGE, NEW JERSEY, ASSIGNOR TO THE SAFETY CAR HEATING & LIGHTING COMPANY, A CORPORATION OF NEW JERSEY.

ELECTRIC SWITCH.

Specification of Letters Patent.

Application filed November 12, 1909. Serial No. 527,589.

To all whom it may concern:

Be it known that I, HARRISON G. THOMP- soN, a citizen of the United States, residing in Glen Ridge, county of Essex, and State of New Jersey, have invented new and useful Improvements in Electric Switches, of which thefollowing is a description.

My invention pertains to that class of electric switches adapted to automatically open and close an electric circuit under predetermined conditions.

My invention has for its particular object to provide means whereby an electric circuit may be established automatically under pre determined conditions and another circuit, or plurality of circuits, automatically manipulated in a desired manner by the operation of the switch.

As my improved switch is particularly useful in cases where it is desired toclose a circuit when a certain voltage shall be reached and simultaneously open a plurality of circuits during said closing action and vice versa, the same will be described with reference to a switch employed by me for carrying out these functions.

In the drawing Figure 1 shows a front elevation of my improved switch. 7

Fig. 2 shows a top plan of the-same, and

Fig. 3 is a section of a portion of the said switch taken through the line AB.

Referring now to the drawings in detail 1 represents a field frame or support of my improved switch adapted to be fastened in any desired location as by means of the lugs 2. The frame 1 is preferably made of iron or other magnetic material and is provided with a central tube 3 made of brass or other non-magnetic material and surrounded by the coil of an electro-magnet or solenoid 4. of fine wire properly chosen for the circuit across which it is to be placed and surrounded by the windings 5 preferably made of a conducting ribbon wound edgewise into the spiral as indicated in section in Fig. 3, the turns of said spiral being insulated from each other as, for instance, coated with shellac or other suitable varnish. One end of the winding 4 is carried out as by means of conductor 6 which may be clamped under the screw- 7 upon the lug 8 attached to the frame 1 as by means of screws 9 and 1nsulated therefrom as by means of insulat ing member 10 and bushings 11. The other end of the coil of the magnet 1 's brought cated in dotted lines at 32.

out as by the conductor 12 and connects with the varlable resistance 65, the function of which will hereinafter more fully appear.

One end of the winding 5 is brought out as indicated at 13 and fastened to the lug 8 as by screws 14. The other end of the said winding is led out as indicated at 15 and connected to the metallic member 16 which 'bon contact member 21 attached thereto as by screw 22. Upon the opposite side of the frame 1 there is placed the contact member 23 to which connections to line may be established as by means of the screws 24. The member 23 is insulated from the frame 1 as by means of insulating member 25, washer 26 and bushing 27 and is provided with a contact face 28 and with a carbon contact 29. 30 represents a plunger or core made of iron or other suitable magnetic material free to move within the tube 3 and held from revolving therein by means of the brass screw 31 engaging the slot inclifiexible contact member adapted when raised to cause contact against the surfaces and 28 so as to electrically connect the member 16 withthe member 23. The member 33 is preferably made of a number of strips of thin elastic metal riveted together and attached to the metallic washer 34: against which rests a metallic conducting spring 35.

The parts 33, 34 and 35 are held in place and attached to the plunger or core as by means of screw 36 and insulated therefrom as by means of washers 37 and 38 and bushing 66. The spring is provided at 1ts extremities with carbon contact members 39.

The upper side of the frame 1 carries the member 10 insulated therefrom as by the member 41 and to which is pivotally attached the rocking member 42 as by means of screw pin 43. The member 412 carries the flexible contact member 14 attached thereto as by screws 45 adapted to cause contact siniultaneously with the various contact members 46 attached to the frame 1 as by screws 47 and insulated therefrom as by member 18 which may be connected with various electric circuits as by means of screws 49 and the member 42 may be con- 33 represents a nected in circuit as by means of the screw 50. The member l2 is normally pressed downward as by the adjustable compression springs 51 passing over the screiwthreaded rods 52 provided with suitable nuts for forcing the springs 51 against the insulating washers 53 resting upon the member The rod 52 passing through the apertures 54 in the member 42 are threaded into the frame 1 and have slipped thereover the sleeves 56 and insulating washers 55 which serve to limit the downward movement of the member 4L2 under the action of springs 51. The plunger or core 30 is provided with an extension made of non-magnetic material and passing through the aperture in the member 1 as indicated in Fig. The member 57 carries the insulating washer 58 and the screw rod 59 passing through the aperture 60 in the member 42 and carrying the insulating washer 61 and adjustable nuts 62 and 63 which may be locked together as by means of screw Get.

The operation of my improved switch is substantially as follows:

The coil of the magnet 4 is connected across the circuit which it is desired to have operate the switch when its voltage rises and falls to certain predetermined limits as by means of conductors 6 and 12 through a suitable adjustable resistance as indicated diagrammatically at 65, the adjustment of which will determine within certain limits the voltage at which the switch shall close as will hereinafter more plainly appear. The winding 5 may be placed in series with the main circuit to be operated by the switch in certain cases so as to insure a good contact when carrying heavy currents and to cause the switch to open upon reversal of the current as. for instance, when charging storage batteries and as my improved switch is largely used for this purpose, it is shown and described with the winding 5 so connected as indicated at 13 and 15, and as this circuit is often the one the voltage of which shall determine the closing of the switch, the operation is described with reference to said conditions and one branch of the magnet 4 to wit: the terminal 6, is connected with one end of the winding 5 as by screw 7 connecting with the h1g8 to which the terminal 13 is attached as by screw 14. By properly adjusting the resistance 65 and the vertical position of the core 30, as by means of the nuts 62 and 63, the voltage at which said core will be lifted against the action of gravity may readily be determined and when this 'oltage is reached and the core lifted contact will be made between the carbon members 39 and the carbon members 21 and 29 under which conditions current flowing. through the winding 5. member 16, contact member 21, member 3-). spring 85. member 39 member 29 and member 23 will cause the said winding 5 to tend to further raise the core 30 and form contact between the member 33 and the contact surfaces 20 and 28. In practice I so adjust the switch that when the core 30 is suliiciently raised to cause contact between the members 39 and 21 and 29 so as to complete a circuit through the winding the extension 57 will have lifted the washer 58 until the same has struck the underside of the member 42 in such manner that further elevation of the plunger 30 will lift the member 12 and tend to break the connection between the member -l-land the members -16. Then, by the ad justment of the spring 51 l determine the amount of current necessary to flow through the winding in order to further lift the plunger 30 and close the circuit through the member 3;) and open the circuit between members 4:4 and 46 and l have often found it advantageous in practice to have these two actions to wit: the closing of the circuit by the member and the opening of the circuit by the movement of the members 44-, take place simultaneously. It will be ohvious from the above description that if the magnets 4i and 5 are so wound as to assist each other in the above outlined operation any reversal of current in said winding 5 as. for instance, a back discharge from the battery to the generator will tend to weaken the effect of magnet 4. instead of assist it and in that way insure the opening of the switch by first breaking the contact caused by the member 33 against the surfaces 20 and 2S and if desired simultaneously establish contact between the member 44 and the various members 46 and then break the current flowing back through the winding 5 at the carbon members 2139 and 2f) 39 where slight sparli'ing due to the brca k will cause no damage.

From the foregoing it will be obvious that l have produced a switch compact in construction. capable of withstanding the rough usage necessarily suffered by this type of automatic device and that the same is capable of various adjustments to meet the various uses to which the same is applicable.

I do not wish in the exact way to limit myself to any details of construction or exact mode of operation of my improved switch as described in this specification inasmuch as the above description is intended merely to enable one skilled in the art to make and use a switch embodying the essentials of my invention and it is obvious that wide departure in the way of details of construction and operation may be made and still be within the scope of my invention which is as set forth in the following claim to wit:

in an electiomagnetic switch, a high 1csistance coil and a low resistance coil, a magnetic core subject to the combined flux of both coils and carrying main and shunt contacts so related to the device that the shunt and main contacts are engaged successively, one end of the low resistance coil being connected to one of the main contacts, a pivoted switch arm and a stationary switch contact at the other end of the device, a 10st motion connection between the similar end of the core and the switch arm, and adjustable resilient means acting on 10 said switch arm in opposition to the movement of the core due to the flux.

HARRISON Gr. THOMPSON. lVitnesses J OHN T. CLARK, E. E. ALLBEE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

